Ultra-thin copper foil with carrier and printed wiring board using ultra-thin copper foil with carrier

ABSTRACT

To produce an ultra-thin copper foil with a carrier foil that microscopic crystal grains can be deposited without being affected by the surface roughness of a carrier foil, etching can be performed until an ultra-fine width such that line/space is 15 μm or less, and the microscopic line and a wiring board have large peel strength even after line of 15 μm is etched. An ultra-thin copper foil wherein a carrier foil, a peeling layer, an ultra-thin copper foil are laminated in this order, the ultra-thin copper foil (before roughening treatment is performed) is an electrolytic copper foil that surface roughness of 2.5 μm as ten point height of roughness profile, and the minimum distance between peaks of salients of a based material is 5 μm or more. Moreover, the surface of the ultra-thin copper foil is performed roughening treatment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultra-thin copper foil with acarrier foil used at the time of producing a printed wiring board. Inparticular, the present invention relates to an ultra-thin copper foilwith a carrier foil used preferably for producing a printed wiring boardfor high density ultra-fine wiring or a multilayer printed wiring board.

2. Description of the Related Art

A printed wiring board is produced as mentioned below.

First, after placing a thin copper foil for forming a surface circuit ona surface of an insulative substrate consisting of a glass epoxy resinor a polyimide resin and so on, by heating and laminating, a copper cladlaminate is produced.

Next, after placing a through hole and a through hole plating areperformed sequentially, an etching process is performed to a copper foilin the surface of the copper clad laminate, a wiring pattern having adesired line width and desired pitches of adjacent lines are formed, andfinally, forming of a solder resist and other finishing processes areperformed.

In the copper foil used at that time, a surface of the side that islaminated to a substrate is defined as a treatment side, an anchoringeffect is exhibited on the substrates by the treatment side to improvethe peel strength between the substrate and the copper foil to assurereliability as the printed wiring board.

Further, recently, the treatment side of the copper foil is covered witha resin for bonding such as an epoxy resin, and the copper foil withresin that this resin for bonding is made to an insulating resin layerin semi-cured state (B stage) is used as a copper foil for forming asurface circuit, then a printed wiring board, in particular a build upwiring board is produced by laminating side of the insulating resinlayer to substrate.

Moreover, corresponding to high integration of various electronic parts,in such a build-up printed wiring board, density growth is needed for awiring pattern, and there has been a demand for a printed wiring boardwith wiring patterns consisting a wiring of fine line widths and pitchesof adjacent lines, that is to say, fine patterns. For example, in thecase of a printed wiring board used for a semiconductor package, aprinted wiring board having a high density ultra-fine wiring of whichline widths and pitches of adjacent lines are around 15 μm respectivelyhas been demanded.

If a thick copper foil is used as a copper foil for a high densityultra-fine wiring board of such a printed wiring board, the time that isnecessary for etching until reaching a surface of a substrate becomeslonger. As a result, the verticality of the sidewalls of the wiringpatterns formed is ruined, an etching factor indicated in the followingequation Ef becomes smaller.Ef=2H/(B−T)

H is the thickness of a copper foil, is the bottom width of a formedprinted wiring board.

T is the top width of a formed printed wiring board.

These problems are not serious in the case that the line width of wiringin the formed wiring pattern, however, it may lead to disconnection inthe case of the wiring pattern of which line width is narrow.

On the contrary, in the case of a thin copper foil, the etching factorEf can be larger.

Incidentally, peel strength of a conventional copper foil and asubstrate assures peel strength by depositing copper grains on thesurface of the side bonded with the substrate to be the treatment sideand by embedding a protrusion of the copper grains of this copper foilto the substrate. Consequently, until the embedded protrusion of thecopper grains is removed completely from the substrate, a copper remains(this phenomenon is usually called as treatment transfer after etching,it may be a cause that insulation failure is occurred in the case thatthe pitches of adjacent lines of the wiring pattern is narrow. The timefor etching-removing this embedded protrusion of the copper grainscompletely does not greatly affect the wiring pattern, however theetching time affects greatly in the case that the thickness of thecopper foil is thin. That is to say, since the etching time to removethe embedded protrusion becomes longer in comparison to the etching timeof the copper foil, in the process of etching-removing the embeddedprotrusion, an etching of side wall of the wiring pattern already formedprogresses, as a result, the Ef value becomes smaller.

In the case of using a thin copper foil, in fact, such a problem can besolved if the surface roughness is made smaller, however, in that case,it is difficult to produce the printed wiring board having the reliableand fine wiring pattern, since the peel strength between the copper foiland the substrate becomes smaller.

Moreover, in the case of the thin copper foil, since the mechanicalstrength is small, wrinkles and creases cause easily, further the copperfoil may go out when producing a printed wiring board, therefore thereis a problem that the greatest care is required for handling.

As mentioned above, it is considerably difficult to produce a printedwiring board having fine wiring pattern that the Ef value is large andthat the peel strength is large as a practical matter. In particular, itis virtually impossible to form the wiring pattern with a high densityultra-fine wiring of which interval of lines or line width is around 15μm by using a commercially available copper foil, and in fact, it isstrongly desired to develop a copper foil for permitting that.

As such a copper foil used for high density ultra-fine wiring (finepattern) of which interval of lines or line width is around 15 μm, acopper foil having the thickness is 9 μm or leas, in particular 5μm orless is suitable.

As such an ultra-thin copper foil used for a fine pattern, the applicantof the present invention discloses the following techniques.

In Japanese Unexamined Patent Publication No. 2000-269637, a copper foilcharacterized that it is an ultra-thin copper foil with a carrier foil,a copper foil having a surface roughness Rz is 1.5 μm or less is definedas a carrier foil, on the surface a peeling layer and an electrolyticcopper plating layer are laminated in this order, and the surface of theoutermost layer of the electrolytic copper plating layer is defined as atreatment side is disclosed.

In Japanese Unexamined Patent Publication No. 331537, a copper foil witha carrier foil is an ultra-thin copper foil wherein a copper foil isdefined as a carrier foil, on the surface a peeling layer and anelectrolytic copper plating layer are electroplated in this order, and acopper foil with a carrier foil characterized that a portion adjacent toright-and-left edges between the copper foil with a carrier foil and theelectrolytic copper plating layer is made to be connected strongly incomparison to a middle portion of them and that the outermost surface ofthe electrolytic copper plating layer is roughened are disclosed.

In Published Japanese Translation of a PCT Application No. 2003-524078,a copper foil characterized that a carrier foil that is smoothed to makea mat surface roughness Rz is 3.5 μm or lees is used, on the mat surfacea peeling layer and an electrolytic copper plating layer areelectroplated in this order, and the outermost surface of theelectrolytic copper plating layer is defined as a treatment side isdisclosed.

These copper foils with a carrier foil are shown in FIG. 4. Theultra-thin copper foil with a carrier foil has the peeling layer 2 andthe electrolytic copper plating layer (copper foil) 4 formed in thisorder on one side of the copper foil as a carrier 1 (called as the“carrier foil” below), and consists of the treatment side 4 a formed byelectrodepositing a roughening grain of a copper 5 on the exposedsurface (surface) of the electrolytic copper plating layer 4.

Further, after overlapping the treatment side 4 a on a glass-epoxysubstrate (not illustrated), the whole is laminated, next bypeeling/removing the carrier foil 1 the side of junction of theelectrolytic copper plating layer and the carrier foil is exposed, thepredetermined wiring pattern is formed there.

The carrier foil 1 functions as a reinforcing material (carrier) thatback up the thin electrolytic copper plating layer 4 until contacting tothe substrate. Further, the peeling layer 2 is a layer for peelingeasily when separating the above electrolytic copper plating layer(copper foil) 4 and the carrier foil 1, hence the carrier foil 1 can bepeeled clearly and easily. Note that the peeling layer 2 is removed withthe carrier foil 1 together when peeling and removing the carrier foil1.

On the contrary, on the electrolytic copper plating layer (copper foil)4 that is attached with the glass epoxy substrate, after placing athrough hole and a through hole plating are performed sequentially, anetching process is performed to a copper foil that is in the surface ofthe copper clad laminate, a wiring pattern 1, having a desired linewidth and desired pitches of adjacent lines is formed, and finally,forming of a solder resist and other finishing processes are performed.

Since a fine pattern can be formed and handling ability is superior inhandling, such a copper foil with a carrier foil, in particular anultra-thin copper foil of which thickness is very thin obtains anassessment that it is a suitable copper foil when producing a build-upwiring board in particular is obtained. However, meanwhile, thefollowing point at issue is actualized.

The conventional electrolytic copper plating layer 4 is, as shown inFIG. 1, a portion of a salient and a portion of a depression exist onthe surface (hereinafter these are defines as a salient of a basedmaterial).

When roughening grains 5 are electrodeposited on such a surface,roughening grains are electrodeposited intensively at the portion of asalient and are not electrodeposited aboundingly at the portion of adepression.

A copper foil of such a shape improves peel strength with a resinsubstrate, whereas is hardly dissolved and causes “treatment transferafter etching”.

Conventionally, in a treatment side deposited such a roughening grain,Rz was around 3.5 μm, it was limit that a thin line of which line/spacewas about 30 μm/30 μm to 25 μm/25 μm was formed, if the surface afterroughening treatment was not smooth, it was impossible to formline/space was 15 μm/15 μm that is the to be a megatrend of a comingsemiconductor package substrate.

Moreover, the surface roughness Rz is a ten point height of roughnessprofile described in Japanese Industrial Standards B 0601-1994.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an ultra-thin copperfoil that a wiring of line/space is about 15 μm/15 μm can be formed on awiring board and having peel strength that is necessary to laminate witha wiring board.

An ultra-thin copper foil with a carrier foil of the first aspect of thepresent invention is characterized that a peeling layer, an ultra-thincopper foil are laminated in this order on a carrier foil, and theultra-thin copper foil is an electrolytic copper foil that surfaceroughness of 2.5 μm as ten point height of roughness profile, and theminimum distance between peaks of salients of a based material is 5 μmor more.

An ultra-thin copper foil with a carrier foil of the second aspect ofthe present invention is characterized that a peeling layer, anultra-thin copper foil are electroplated in this order on a carrierfoil, and the ultra-thin copper foil is an electrolytic copper foil thatsurface roughness of 2.5 μm as ten point height of roughness profile,the minimum distance between peaks of salients of a based material is 5μm or more, and a crystal grain having average grains diameter is 2 μmor less is deposited on the surface.

In an ultra-thin copper foil with a carrier foil that a peeling layerand an ultra-thin copper foil are electroplated in this order on acarrier foil, an ultra-thin copper foil with a carrier foil of the thirdaspect of the present invention, has an exposed surface that chemicaltreatment and/or electrochemical treatment in the range without changinga profile of the exposed surface are performed.

In an ultra-thin copper foil with a carrier foil of the fourth aspect ofthe prevent invention, treatment of making unevenness is performed to anexposed surface of the ultra-thin copper foil by chemical etching and/orelectrochemical etching, and on the uneven processed surface, chemicaltreatment and/or electrochemical treatment are performed in the rangewithout changing a profile of the uneven processed surface.

In an ultra-thin copper foil with a carrier foil of the fifth aspect ofthe present invention, it is preferable that an exposed surface isperformed roughening treatment, and it is preferable that in theroughening treatment a copper microscopic grain is formed byelectrodepositing.

Further, on the treatment side, chemical treatment and/orelectrochemical treatment are performed within a range that profile ofthe treatment side does not change.

Note that in the present invention, an ultra-thin copper foil is acopper foil having the thickness of 0.1 μm or more and 9 μm or less.Because the copper foil of less than 0.1 μm has many pinholes so that itis impractical, the foil more than 9 μm does not require to add acarrier.

It is preferable that the peeling layer is formed by Cr, Ni, Co, Fe, Mo,Ti, W, P, and/or these alloy metal layer or these hydrous oxide layer.Moreover, it is effective that the peeling layer is formed by an organicfilm.

The first aspect of the present invention is an ultra-thin copper foilwith a carrier foil characterized that a peeling layer and an ultra-thincopper foil are electroplated in this order on a carrier foil, theultra-thin copper foil is an electrolytic copper foil that the surfaceroughness is 2.5 μm or less in ten point height of roughness profile andthe minimum distance of peaks of salients of a based material is 5 μm ormore.

The second aspect of the present invention is an ultra-thin copper foilwith a carrier foil characterized that a peeling layer and an ultra-thincopper foil are electroplated in this order on a carrier foil, theultra-thin copper foil is an electrolytic copper foil that the surfaceroughness is 2.5 μm or less in ten point height of roughness profile,the minimum distance of peaks of salients of a based material is 5 μm ormore, and crystal grains of which average grain diameter is 2 μm or lessare deposited on the surface.

The third aspect of the present invention is that the surface of theultra-thin copper foil is not performed roughening treatment, andchemical and/or electrochemical treatment are performed on the surfaceof the ultra-thin copper foil.

The reason that Rz of the surface of the ultra-thin copper foil isnecessary to be 2.5 μm and the minimum distance between peaks ofsalients of a based material is necessary to be 5 μm or more is becauseit is impossible that fine lines of line/space=15 μm/15 μm or less canbe formed in the foil that a salient of a based material is high and thedistance between peaks is thick, even in the case that rougheningtreatment is not performed on the surface.

An ultra-thin copper foil of the present invention, for example, asillustrated in FIG. 4, is a copper foil that chemical treatment and/orelectrochemical treatment are performed on the surface of the copperfoil of the present invention without depositing a copper rougheninggrain (the roughening grain 5 in FIG. 1) on the surface of theultra-thin copper foil 4.

As mentioned above, on the surface of a conventional ultra-thin copperfoil with a carrier foil, for improving peel strength with thesubstrate, copper roughening grains are deposited. By using copperplating solution including selenium, tellurium, arsenic, antimony,bismuth and so on usually that is different from plating solutionforming the ultra-thin copper foil (for example, refer to Japaneseexamined patent application publication No. 1978-39327) and by treatingin high current density adjacent to limit current density of copper, theabove roughening grains are deposited. Therefore, the elements are takenin roughening grains deposited on the surface of the copper foil, as aresult, the surface of the ultra-thin copper foil and the rougheninggrain layer are constituted by layers that the crystal structure andcomposition are different. Etching time of the grains of compositionincluding the dopant elements is longer in comparison with etching timeof the copper constituting the copper foil, therefore, when the patternis etched by the etching solution, the roughening grain layer is hard tobe etched and leads to “treatment transfer after etching”.

In the copper foil of the present invention, the roughening grains thatleads to “treatment transfer after etching” do not exist, because a finewiring can be formed by forming wiring by etching.

On the contrary, a copper foil that roughening grains is not depositedhas small anchoring effect and is hard to obtain large peel strengthwhen bonding with a resin substrate. The present invention is to producean ultra-thin copper foil with a carrier foil that a fine wiring isformed without reducing the adhesive strength with resin substrate byperforming chemical treatment and/or electrochemical treatment to adegree without changing the surface profile of the copper foil beforethe surface treatment, and by improving chemical bonding (peelstrength).

In the present invention, the chemical treatment is oxide treatment,hydrous oxide treatment, silane coupling agent treatment and so on. Bythese treatment, the etching speed of the processed surface is quickenedup as fast as or faster than the etching speed of the copper foil initself, therefore without reducing the etching factor peel strength withthe resin substrate can be improved.

The chemical treatment improving peel strength varies by kind of theresin substrate, however, for a polyimide resin, a glass epoxy resin, itis preferable to perform hydrous oxide treatment such as copper oxidetreatment, chromate treatment and so on.

Silane coupling agent treatment has dissimilar peel strength by a resin,however, treatment using vinyl silane, epoxy silane, styryl silane,methacryloxy silane, acryloxy silane, amino silane, ureido silane,chloropropyl silane, mercapto silane, sulfide silane, isocyanate silaneand so on is preferable.

Moreover, in the present invention, the electrochemical treatment isplating treatment such as single metal plating, alloy metal plating, anddispersion plating (plating that oxide is dispersed in metal matrix) andso on, or anodizing treatment and so on. By kind of the resin substrateplating treatment improving the peel strength is various, for apolyimide resin, nickel/nickel alloy plating, chromium/chromium alloyplating and so on are effective. Moreover, for a glass epoxy resin, zincplating, zinc-chromium alloy plating and so on are effective. Further,copper oxide treatment formed by anodizing treatment is effective for aglass epoxy resin.

The composition of the plating may be selected so that the etching speedof the surface processed by the electrochemical treatment may beselected does not become slower than the etching speed of the copperfoil in itself. If the composition that the etching speed becomes slowis selected, it is necessary to be the thickness so that the etchingspeed does not become slow.

For example, in the case of zinc plating, the etching speed of that isfaster than copper plating. However, in the case of nickel plating orchromium plating, the etching speed is slower than the etching speed ofcopper plating.

In the case that nickel or chromium is selected, it is necessary todeposit the amount of the degree that the peel strength can be improvedbut the etching speed cannot vary. Concretely, in the case or nickel orchromium, it is effective to deposit 0.01 mg/dm² to 0.5 mg/dm². Becausein the case of being below 0.01 mg/dm² the affect for adhesiveness isreduced, and in the case of being over 0.5 mg/dm² the etching speedslows.

Moreover, in similar to the case of treatment by alloy metal plating ordispersion plating, the alloy composition is selected so that theetching speed does not become slower than the etching speed of thecopper foil in itself, or in the case that the composition that theetching speed becomes slow, it is necessary to be the thickness so thatthe etching speed does not become slow.

Note that the speed by treatment by anodization of copper is faster thanthe etching speed of copper.

In the present invention, the amount of deposited element onto thesurface of copper foil of chemical treatment and/or electrochemicaltreatment to a degree without changing the surface profile is preferableto be about 0.01 mg/dm² to 30 mg/dm². It is because in the case of thedeposited amount less than 0.01 mg/dm², it is not very effective toimprove the peel strength, in the case over 30 mg/dm2, the effect toimprove peel strength is saturated and the surface profile changes andabnormal electrodepositing occurs.

An ultra-thin copper foil with a carrier foil of the present invention,for example, as illustrated in FIG. 5, is characterized that treatmentof making unevenness is performed by the chemical etching on theultra-thin copper foil, and/or treatment of making unevenness isperformed by the electrochemical etching on the ultra-thin copper foil,further characterized that chemical treatment and/or electrochemicaltreatment are performed on the surface of the ultra-thin copper foil toa degree that the profile does not change.

The treatment of making unevenness by the chemical etching is treatmentof roughening the surface of the copper foil by using etching solutionsuch as sulfuric acid-hydrogen peroxide water and so on or commerciallyavailable surface roughening solution. Therefore, since the surface ofthe ultra-thin copper foil in itself is roughened, peel strength withthe resin substrate improves, and since the roughening grains thatcrystal structure or composition are different are not deposited,“treatment transfer after etching” hardly occurs in comparison with aconventional ultra-thin copper foil with a carrier foil when etching,finer pattern can be formed.

Moreover, electrochemical etching uses single sulfuric acid solution,sulfuric acid-copper sulfate solution, hydrochloric acid solution ornitric acid for electrolytic solution, and is etching treatment thatelectric current is passed and treatment of etching and depositingcopper nodule.

For the current waveform of this case, direct current (the ultra-thincopper foil is charged +), alternate current, PR current (± inverteddirect current), pulse current (the ultra-thin copper foil is charged +)and so on are used.

In this case, the surface shape is different by the case of using singlesulfuric acid solution or sulfuric acid-copper sulfamate solution andthe case of using hydrochloric acid solution or nitric acid forelectrolytic solution for electrolytic solution.

In the case of using single sulfuric acid solution or sulfuricacid-copper sulfamate solution for electrolytic solution, if treatmentis performed by using alternative current or PR current (± inverteddirect current), etching operation (anodic dissolution) and operation ofdepositing copper nodule (cathodic electrodeposition) are occurredalternately to become unevenness that pit formed by etching operation onthe surface and small copper nodule are deposited. Correspondingly, inthe case of using hydrochloric acid solution or nitric acid forelectrolytic solution, etching operation (anodic dissolution) onlyoccurs and operation of depositing copper nodule (cathodicelectrodeposition) does not occur, hence only pit formed by etchingoperation on the surface occurs,

In the above case, that is using sulfuric acid solution or sulfuricacid-copper sulfamate solution, excepting for using alternate current orPR current (± inverted direct current), small pit is occurred on thesurface of the ultra-thin copper foil and peel strength with the resinsubstrate is improved. Further, since also in this case the rougheninggrains leading to “treatment transfer after etching”, when etchingwiring, fine wiring can be formed.

In the case of using sulfuric acid solution or sulfuric acid-coppersulfamate solution and the case that using alternate current and PRcurrent (± inverted direct current), small copper nodule is depositedwith occurring pit. However, in this case, since small copper nodule isa thing that a portion of the ultra-thin copper foil is re-deposited andcomposition of it is equal to the ultra-thin copper foil in itself, incomparison with a conventional roughening treatment grain, when patternis etched, small copper nodule is easily etched and “treatment transferafter etching” is hardly occurred. Therefore, finer pattern can beformed.

In the copper foil of the present invention, since the roughening grainof which etching speed is slower than the copper foil in itself is notdeposited on the surface of the copper foil, when wiring is etched,“treatment transfer after etching” is not occurred, and fine wiring of15 μm or less can be formed. Even after etching lines of 15 μm or less,since chemical treatment and/or electrochemical treatment that improvepeel strength with the resin are performed, the microscopic lines andthe wiring substrate (resin substrate) have large peel strength.

Therefore, the printed wiring board that the high density ultra-finewiring is preformed can be produced by the ultra-thin copper foil with acarrier foil of the present invention, moreover the multilayer printedwiring board the high density ultra-fine wiring is preformed can beproduced by the ultra-thin copper foil with a carrier foil of thepresent invention.

The present invention is an ultra-thin copper foil with a carrier foilthat a peeling layer, an ultra-thin copper foil are electroplated inthis order on a carrier foil, and the ultra-thin copper foil is anelectrolytic copper foil that surface roughness of 2.5 μm as ten pointheight of roughness profile and the minimum distance between peaks ofsalients of a based material is 5 μm or more.

Moreover, the present invention is an ultra-thin copper foil with acarrier that a peeling layer, an ultra-thin copper foil areelectroplated in this order on a carrier foil, and the ultra-thin copperfoil is an electrolytic copper foil that surface roughness of 2.5 μm asten point height of roughness profile, the minimum distance betweenpeaks of salients of a based material is 5 μm or more, and a crystalgrain having average grins diameter is 2 μm or less is deposited on thesurface.

It is preferable that copper microscopic grains are formed byelectrodepositing in the roughening treatment of the ultra-thin copperfoil with a carrier foil. Further chemical treatment and/orelectrochemical treatment are performed on the treatment side within arange that profile of the treatment side does not change.

The reason that Rz of the surface of the ultra-thin copper foil isnecessary to be 2.5 μm and the minimum distance between peaks ofsalients of a based material is necessary to be 5 μm or more is becausethe roughening grains are electrodeposited evenly entirely withoutconcentrating the roughening grains at the peak portion of a salient ofthe based material when the roughening grain 5 is electrodeposited.

Moreover, if the crystal grain of the average grain diameter of 2 μm orless is deposited on the surface, it is possible to electrodeposit amicroscopic grain by being affected by the crystal grain of the base(ultra-thin copper foil) when electrodepositing the roughening grain 5on that.

A copper foil of the present invention has Rz that is controlled to be2.5 μm or less even after roughening grains are deposited, and has largepeel strength between fine lines and a wiring substrate (resinsubstrate) since roughening grains are deposited aboundingly on the 15μm line even after 15 μm line is etched. Therefore, a printed wiringboard that high density ultra-fine wiring is performed can be producedby an ultra-thin copper foil of the present invention, and a multilayerprinted wiring board that high density ultra-fine wiring is performedcan be produced by an ultra-thin copper foil of the present invention.

According to the first to the fifth aspect of the present invention, aprinted wiring board that high density ultra-fine wiring is performed bythe ultra-thin copper foil with a carrier foil is produced.

Moreover, according to the first to the fifth aspect of the presentinvention, a multilayer printed wiring board that high densityultra-fine wiring is performed by the ultra-thin copper foil with acarrier foil is produced.

BREIF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clearer from the following description of the preferredembodiments given with reference to the accompanying drawings, in which:

FIG. 1 is an enlarged cross sectional view of a conventional ultra-thincopper foil with a carrier foil.

FIG. 2 in an enlarged cross sectional view of an Ultra-thin copper foilwith a carrier foil of the first embodiment of the present invention.

FIGS. 3 and 4 are enlarged cross sectional views of ultra-thin copperfoils with a carrier foil of the second embodiment of the presentinvention.

FIG. 5 is an enlarged cross sectional view of an ultra-thin copper foilwith a carrier foil of the third embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described withreference to the accompanying drawings.

The First Embodiment

FIG. 2 shows an ultra-thin copper foil with a carrier foil of the firstembodiment of the present invention, a peeling layer 2 is formed on thesurface of a carrier foil 1, and an ultra-thin copper foil 4 is formedon the peeling layer 2. The ultra-thin copper foil with a carrier foilof the first embodiment of the present invention is constituted bylaminating the carrier foil 1, the peeling layer 2 and the ultra-thincopper foil 4.

The surface roughness Rz of the surface of the ultra-thin copper foil 4is 2.5 μm or less and the minimum distance between peaks of salients ofa based material is 5 μm or more, and a roughening grain layer 5consisting of roughening grains 4 a is formed on the surface.

To produce the surface of the ultra-thin copper foil 4 of which thesurface roughness Rz is 2.5 μm or less and the minimum distance betweenpeaks of salients of a based material is 5 μm or more, plating is formedby a copper plating solution that can generate a smooth surface andmirror gloss.

As the copper plating solution that can generate a smooth surface andmirror gloss, it is optimal that the copper plating solution disclose inJapanese Patent No. 3313277 or the solution containing a commerciallyavailable gloss plating dopant for decoration is used. since theultra-thin copper foil 4 obtained from these plating solution has smallsurface roughness, and has a flat surface condition, further crystalgrains having average grain diameter of 2 μm are deposited, even in thecase that a copper roughening grains are deposited, to form evenlymicroscopic grains having average grain diameter of 2 μm as illustratedas a small points in FIG. 2.

Note that the average grain diameter of the crystal grain of the foilitself is the calculated value that first, a picture of the surface thatthe crystal grains are formed is taken by a transmission electronmicroscope (TEM), the area of the crystal grain in the picture ismeasured over ten point and the diameter is calculated when the crystalgrain is defined as a perfect circle.

Moreover, the average grain diameter of the microscopic grains is anaverage value that is measured actually in SEM and is measured over tenpoints.

It is preferable that the peeling layer 2 set on the carrier foil 1consists of Cr, Ni, Co, Fe, Mo, Ti, W, P and/or these alloy layer orthese hydrous oxide layer, or an organic film.

It is preferable that these metals (including alloy metal) and thosehydrous oxides forming the peeling layer 2 are formed by cathodicelectrolytic treatment. Note that in a stage that wiring board that theultra-thin copper foil with a carrier foil is used is formed, forstabilizing the peeling after laminating the ultra-thin copper foil witha carrier foil on the insulating substrate, nickel, iron or these alloylayer may be set together under the peeling layer 2.

As preferable binary alloys of chromium alloy for the peeling layer 2,nickel-chromium, cobalt-chromium, chromium-tungsten, chromium-copper,chromium-iron, chromium-titanium can be mentioned. As the ternary alloy,nickel-iron-chromium, nickel-chromium-molybdenum,nickel-chromium-tungsten, nickel-chromium-copper,nickel-chromium-phosphorus, cobalt-iron-chromium,cobalt-chromium-molybdenum, cobalt-chromium-tungsten,cobalt-chromium-copper, cobalt-chromium-phosphorus, etc. can bementioned.

Moreover, in the case of using an organic film for the peeling layer 2,it is preferable that a thing consisting of one kind or two kind or moreselected from among an organic compound including nitrogen, an organiccompound including sulfur or a carboxylic acid is used.

The peel strength at the time of peeling the carrier foil 1 from thepeeling layer 2 is influenced with the amount of deposition of thesemetals. That is, if an peeling layer 2 is thick (that is, if there isthe large amount of deposition of plated metal), the surface of thecarrier foil 1 is covered with the metal constituting the peelingmaterial (hereinafter called as peeling layer metal) completely, it isconsidered that the peel strength corresponds to the peeling power whichtears off the joint surfaces between the surface of the peeling layermetal and the ultra-thin copper foil 4 stacked afterward.

On the other hand, when a peeling layer 2 is thin (that is, if there isthe small amount of deposition of plated metal), the surface of thecarrier foil 1 is not completely covered with the peeling layer metal,it is thought that the peel strength is the peeling power which tearsoff the joint surfaces between the carrier foil 1 which is exposedslightly and the peeling layer metal and the ultra-thin copper foil 4deposited on them.

Therefore, the peel strength of the carrier foil 1 and the ultra-thincopper foil 4 changes with the amount of deposition of plated metal thatforms a peeling layer 2, however, since if a peeling layer 2 is formed(deposited) to some extent thickly, the peel strength will not changeany more, even if the amount of deposition of the metal which forms apeeling layer 2 is made 100 mg/dm² or more, the peel strength does notchange.

Hereinafter, examples of the ultra-thin copper foil with a carrier foilof the first embodiment of the present invention and comparativeexamples will be described.

EXAMPLE 1

(1) Making of an Ultra-Thin Copper Foil

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.2 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, by using a copper sulfate solution describedin the following composition 1 as an electrolytic solution andperforming the electrolysis in a condition that the current density was30 A/dm² and the temperature of the solution was 50 degrees C., anultra-thin copper layer (copper foil) having the thickness of 5 μm waselectroplated. (Composition 1) copper sulfate (CuSO₄.5H₂O)  250 g/l to350 g/l sulfuric acid (H₂SO₄)   80 g/l to 120 g/l 3-mercapto-1-sodiumpropanesulfonate  0.5 ppm to 5 ppm hydroxyethyl cellulose   1 ppm to 10ppm low-molecular-weight glue (molecular weight 3000)   1 ppm to 10 ppmCl⁻   10 ppm to 50 ppm

On the ultra-thin copper foil in the following condition, the cathodicelectrolytic treatment by direct current and copper microscopicroughening grains were electrodeposited. (2-1) Forming microscopic graincore (a) Composition of the electrolytic solution copper sulfate(CuSO₄.5H₂O)   80 g/l to 140 g/l sulfuric acid (H₂SO₄)  110 g/l to 160g/l sodium molybdate (Na₂MO₄.2H₂O) 0.05 g/l to 3 g/l ferrous sulfate(FeSO₄.7H₂O)   1 g/l to 15 g/l (b) Temperature of the electrolyticsolution:   35 degrees C. (c) Current density:   10 A/dm² to 50 A/dm²(d) Treatment time:   2 seconds to 15 seconds (2-2) Capsule plating (a)Composition of the electrolytic solution copper sulfate (CuSO₄.5H₂O) 200 g/l to 300 g/l sulfuric acid (H₂SO₄)   90 g/l to 130 g/l (b)Temperature of the electrolytic solution:   60 degrees C. (c) Currentdensity:   10 A/dm² to 30 A/dm² (d) Treatment time:   2 seconds to 15seconds

On the obtained ultra-thin copper foil that copper grains weredeposited, nickel-phosphorus plating (Ni 0.1 mg/dm²) and zinc plating(Zn=0.1 mg/dm²) were performed, further additionally after chromatetreatment (Cr=0.06 mg/dm²) was performed, epoxy silane coupling agenttreatment (Si=0.004 mg/dm²) was performed.

EXAMPLE 2

(1) Producing an Ultra-Thin Copper Layer

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.2 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, by using a copper sulfate solution describedin the following composition 1 as an electrolytic solution andperforming the electrolysis in a condition that the current density was10 A/dm² and the temperature of the solution was 35 degrees C., anultra-thin copper layer (copper foil) having the thickness of 5 μm waselectroplated. (Composition 2) copper sulfate (CuSO₄.5H₂O)  240 g/lsulfuric acid (H₂SO₄)   60 g/l cupracid 210 by Nihon Schering K.K. makeup agent  0.5 cc/l brightening agent (A)  0.5 cc/l brightening agent (B)using for only complement Cl⁻   30 ppmNote that as the complement of the brightening agent, the brighteningagent (A) and the brightening agent (B) were added 300 cc respectivelyfor amount of the current or 1000 Ah.

(2) Electrodepositing of Microscopic Roughening Grains

On the ultra-thin copper foil in the condition equal to Example 1, thecathodic electrolytic treatment by direct current and copper microscopicroughening grains were electrodeposited.

(3) Surface Treatment

On the ultra-thin copper foil that obtained copper grains weredeposited, the treatment similar to Example 1 was preformed.

EXAMPLE 3

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.9 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface in a way similar to Example 1, a peelinglayer, an ultra-thin copper foil, a roughening grain layer were formed,and next, surface treatment was performed to produce an ultra-thincopper foil with a carrier foil.

EXAMPLE 4

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.8 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface in a way similar to Example 2, a peelinglayer, an ultra-thin copper foil, a roughening grain layer were formed,and next, surface treatment was performed to produce an ultra-thincopper foil with a carrier foil.

EXAMPLE 5

An untreated electrolytic copper foil having the surface (S surface)roughness of 2.4 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface in a way similar to Example 1, a peelinglayer, an ultra-thin copper foil, a roughening grain layer were formed,and next, surface treatment was performed to produce an ultra-thincopper foil with a carrier foil.

EXAMPLE 6

An untreated electrolytic copper foil having the surface (S surface)roughness of 2.4 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface in a way similar to Example 2, a peelinglayer, an ultra-thin copper foil, a roughening grain layer were formed,and next, surface treatment was performed to produce an ultra-thincopper foil with a carrier foil.

COMPARATIVE EXAMPLE 1

(1) Making of an Ultra-Thin Copper Foil

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.2 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, by using a copper sulfate solution describedin the following composition 3 as an electrolytic solution andperforming the electrolysis in a condition that the current density was30 A/dm² and the temperature of the solution was 50 degrees C., anultra-thin copper layer (copper foil) having the thickness of 5 μm waselectroplated. (Composition 3) copper sulfate (CuSO₄.5H₂O) 250 g/l to350 g/l sulfuric acid (H₂SO₄)  80 g/l to 120 g/l low-molecular-weightglue  1 ppm to 10 ppm Cl⁻  10 ppm to 50 ppm

(2) Electrodepositing of Microscopic Roughening Grains

(2-1) Forming Microscopic Grain Core

In a way similar to the way indicated in Example 1, copper grains wereelectrodeposited.

(2-2) Capsule Plating

In a way similar to the way indicated in Example 1, capsule plating waselectrodeposited.

(3) Surface Treatment

In a way similar to the way indicated in Example 1, surface treatmentwas performed.

COMPARATIVE EXAMPLE 2

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.8 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface in a way similar to Comparative example 1, apealing layer, an ultra-thin copper foil, a roughening grain layer wereformed, and next surface treatment was performed to produce anultra-thin copper foil with a carrier foil.

COMPARATIVE EXAMPLE 3

An untreated electrolytic copper foil having the surface (S surface)roughness of 2.4 μm and the thickness of 35 μm was defined as a carrierfoil and on the B surface in a way similar to Comparative example 1, apeeling layer, an ultra-thin copper foil, a roughening grain layer wereformed, and next surface treatment was performed to produce anultra-thin copper foil with a carrier foil.

COMPARATIVE EXAMPLE 4

A rolled copper foil having the surface roughness of 0.6 μm and thethickness of 35 μm was defined as a carrier foil and on the surface in away similar to Comparative example 1, a peeling layer, an ultra-thincopper foil, a roughening grain layer were formed, and next surfacetreatment was performed to produce an ultra-thin copper foil with acarrier foil.

COMPARATIVE EXAMPLE 5

An untreated electrolytic copper foil having the thickness of 35 μm wasformed by using electrolytic solution having composition disclosed inPublished Japanese translation of a PCT application No. 2003-524078 as acarrier foil. On the M surface (having the roughness of 2.0 μm) in a waysimilar to Comparative example 1, a peeling layer, an ultra-thin copperfoil, a roughening grain layer were formed, and next surface treatmentwas performed to produce an ultra-thin copper foil with a carrier foil.

Evaluation of the above Examples and the above Comparative examples wasperformed.

For each ultra-thin copper foil produced in Example 1 to 6, Comparativeexamples 1 to 5, the surface roughness (ten point height of roughnessprofile) Rz of the ultra-thin copper foil, the minimum distance betweenpeaks of salients of a based material, and average grain diameter of thesurface crystal grains were measured respectively, the result wasindicated in Table. 1. TABLE 1 Surface roughness Surface of roughnessShape Average Average 5 μm after Roughness of distance grain copperroughen- Etching of S Copper copper between diameter of plating ing PeelTape property Carrier surface plating plating peaks crystal grainsurface treatment strength peeling (L/S: foil (Rz: μm) solution crystal(μm) (Rz: μm) (Rz: μm) (Rz: μm) (kN/cm) test μm) Example 1 35 μm 1.2composition 1 granulated 8   1.5 1.1 1.9 1.21 not 10/10 MP foil crystalpeeled Example 2 35 μm 1.2 composition 2 granulated off the register 0.80.9 1.6 1.13 not 10/10 MP foil crystal because of peeled mirror surfaceExample 3 35 μm 1.8 composition 1 granulated 8   1.5 1.2 2.0 1.31 not15/15 MP foil crystal peeled Example 4 35 μm 1.8 composition 2granulated off the register 0.8 1.0 1.7 1.14 not 10/10 MP foil crystalbecause of peeled mirror surface Example 5 35 μm 2.4 composition 1granulated 8   4.5 1.3 1.9 1.37 not 15/15 MP foil crystal peeled Example6 35 μm 2.4 composition 2 granulated off the register 0.8 1.1 1.9 1.25not 10/10 MP foil crystal because of peeled mirror surface Comparative35 μm 1.2 composition 3 columnar 4.5 >2.0 2.6 3.4 1.46 peeled 30/30example 1 MP foil crystal Comparative 35 μm 1.8 composition 3 columnar4.5 >2.0 2.9 3.8 1.53 peeled 35/35 example 2 MP foil crystal Comparative35 μm 2.4 composition 3 columnar 4.5 >2.0 3.0 4.0 1.58 peeled 50/50example 3 MP foil crystal Comparative 35 μm foil Surface composition 3columnar 4.5 >2.0 1.2 1.9 1.15 peeled 20/20 example 4 0.6 crystalComparative 35 μm foil M surface composition 3 columnar 4.5 >2.0 2.4 3.21.38 peeled 30/30 example 5 1.8 crystal

1. Measurement of Physicality

About the ultra-thin copper foil with a carrier foil of the presentinvention, even electrodeposition property of copper plating issuperior, and as is clear from Table. 1, by performing copper plating ofthe thickness of 5 μm, even if the surface roughness of former foil isas rough as 2.4 μm, the surface roughness of the surface of theultra-thin copper foil becomes small, the surface roughness afterperforming the roughening treatment is controlled small.

2. Producing of Printed Wiring Board

Next, if a printed wiring board or a multilayer printed wiring board wasproduced by an ultra-thin copper foil in Examples 1 to 6, etching at theultra-fine width like line/space=10 μm/10 μm was possible.

3. Measurement of Peel Strength

The peel strength of the ultra-thin copper foil with a carrier foilproduced in examples 1 to 6 and Comparative examples 1 to 5 wasmeasured. The ultra-thin copper foil with a carrier foil defined aswidth of 10 mm was bonded on FR-4 substrate, next the carrier foil waspeeled, and after plating was performed on the ultra-thin copper foil tobe the thickness of 35 μm, it was peeled to measure the peel strength.The result was indicated together in Table. 1. As shown in Table. 1, inthe usual measure method (width of 10 mm), the peel strength inComparative examples is larger than in Examples.

The peel strength in Comparative examples is larger, because sincesalients and depressions exist on the surface of copper foil beforeroughening, roughening grains are focusing to a salient portion toelectrodeposit, and in a depression portion roughening grains are notelectrodeposited but since the measurement is used wide width as 100 mmthe anchoring effect of the roughening grains occurs to be large peelstrength. However, when width becomes to be ultra-fine width such as 50μm or less, the peel strength is reduced so as indicating below.

4. Peel Strength

The reason that the peel strength of the ultra-thin copper foil producedin the above Comparative examples is reduced in the case width is ultrafine such that the width is 50 μm or less is because the amount of thedeposition of roughening grains in the line width becomes thinner as theline width become thinner. For confirming such a phenomenon, tapepeeling test was performed by the printed wiring board produced by theultra-thin copper foil of the present invention of which line/space=50μm/50 μm and the ultra-thin copper foil of Comparative example, and theresult was indicated in Table. 1.

Note that tape peeling test is evaluated whether the pattern is peeledfrom the resin substrate or not when peeling the above test patternhaving L/S=50 μm/50 μm by bonding adhesive tape.

As shown in Table. 1, in the case of ultra-fine width such thatline/space=50 μm/50 μm, the wiring of the copper foil of Comparativeexamples is easily peeled in comparison with the ultra-thin copper foilof the present invention.

5. Evaluation of Etching Property

The 5 μm foil with a carrier foil of Examples 1 to 6 and Comparativeexamples 1 to 5 was pressed on FR-4 substrate and the carrier was peeledoff.

Afterward, the test patterns having line/space=10 μm/10 μm, 15 μm/15 μm,20 μm/20 μm, 25 μm/25 μm, 30 μm/30 μm, 35 μm/35 μm, 40 μm/40 μm, 45μm/45 μm, 50 μm/50 μm (line length=30 mm, number of lines=10) wereprinted on the surface of the copper foil, and etching was performed incopper chloride etching solution.

The line width in the case that ten lines could be etched withoutbridging was indicated numerically in Table. 1. Etching was possibleuntil 15 μm or less in the ultra-thin copper foil produced in Examples,on the contrary, the lowest value of the ultra-thin copper foil producedin Comparative examples was 20 μm.

As mentioned above, an ultra-thin copper foil with a carrier foil of thefirst embodiment of the present invention has excellent effects suchthat an ultra-thin copper electrolytic foil with a carrier foil thatmicroscopic crystal grains are deposited without being affected by thesurface roughness of the carrier foil can be produced, even afterdepositing roughening grains on the foil Rz can be controlled within 2μm to 3 μm, etching can be performed until ultra-fine width such thatline/space is 15 μm or less, and, even after etching lines of 15 μm orless, since a large number of roughening grains are deposited in theline of 15 μm or less, despite roughness is low, fine lines and wiringboard (resin substrate) have adhesive strength, and adhesive strength islarge. Therefore, a printed wiring board having high density ultra-finewiring (ultra-fine pattern) and a multilayer printed wiring board havingultra-fine pattern can be provided.

An ultra-thin copper foil of the present invention is possible to etchuntil ultra-fine such that line width is 15 μm or less, and has largepeel strength, hence that may not peel from a wiring substrate.

As mentioned above, a copper foil of the present invention can beapplied to a circuit conductor of various kinds of wiring device,printed wiring board can be applied to various kinds of electronicsdevice.

The Second Embodiment

FIG. 3 and FIG. 4 are showing an ultra-thin copper foil with a carrierfoil of the second embodiment of the present invention, a peeling layer2 and an ultra-thin copper foil 4 are electroplated and formed on thesurface of a carrier foil 1.

Roughening treatment is not performed on the surface of the ultra-thincopper foil 4, however, chemical treatment and/or electrochemicaltreatment (that is not illustrated) at a degree that the surface profilemay not be changed are performed. By this treatment, chemical bond witha resin substrate and peal strength are improved.

To form a layer of the ultra-thin copper foil 4, plating is performed bythe copper plating solution not including dopant or the copper platingsolution including dopant.

Here the dopant means inorganic compound dopant such as arseniccompound, molybdenum compound, vanadium compound, nickel compound,cobalt compound, iron compound, tungsten compound, germanium compoundand so on, or organic compound dopant such as glue, gelatin, organicactive sulfur containing compound, organic dye, polymer polysaccharide,cellulose and so on.

In the case of using ouch dopant, it is possible to change a shape ofthe surface by the kind of dopant used.

For example, when performing plating by using sulfuric acid-coppersulfate solution containing glue S that is the above typical organicdopant and chloride ion, the shape of the surface of the ultra-thincopper foil 4 becomes a shape such that salients lie in a row (this iscalled as “salient of a based material”).

In the case that glue and chloride ion are used as the dopants, if thethickness of the copper foil is 9 μm, a shape that the surface roughnessRz of a salient of a based material is around 4 μm and the minimumdistance between peaks of salients of a based material is around 4 μm to5 μm is formed. One embodiment of this cross section is illustrated inFIG. 3.

Here Rz indicates ton point height of roughness profile described inJapanese Industrial Standards (JIS) B 0601-1994.

By selecting a kind of dopant, it is possible to form from a shape thatheight of a salient of a base material is lower than 4 μm and theminimum distance between peaks of salients is less than 5 μm until flatshape like a mirror plane that height of a salient of a base material islower than 4 μm and the minimum distance between peaks of salients is 5μm or more. One embodiment of this cross section is illustrated in FIG.4.

As the height of the salient of a based material becomes lower and thedistance between the peaks of salients of a based material becomelonger, the copper foil becomes more suitable for forming fine pattern.

Moreover, Rz of the surface of ultra-thin copper foil 4 formed fromcopper plating solution not containing component except for copper asmajor component, that is to say, not containing inorganic and organicdopant, can be made about 1 μm to 2 μm and the minimum distance betweenpeaks can be made 5 μm or more by selecting current density and flowvelocity of the electrolytic solution (state of stirring) at the time ofproducing foils. Moreover, since the surface of the ultra-thin copperfoil 4 is a surface shape that a number of small salients anddepressions exist, when producing a printed wiring board by using thisultra-thin copper foil with a carrier foil peel strength with a resinsubstrate is excellent and fine wiring can be formed. Moreover, sinceroughening grain does not exist and organic or inorganic impuritiesincluded in the layer of the ultra-thin copper foil 4 are very few, whenwiring is etched, the fine wiring can be formed.

The Third Embodiment

FIG. 5 is showing an ultra-thin copper foil with a carrier foil of thethird embodiment, and showing a example that treatment of makingunevenness is performed on the surface of an ultra-thin copper foil 4 bychemical etching, and/or treatment of making unevenness are performed byelectrochemical etching.

A peeling layer 2 and the ultra-thin copper foil 4 are laminated andformed on the surface of a carrier foil 1. A small tip 6 is formed onthe surface of the ultra-thin copper foil 4. Further, chemical treatmentand/or electrochemical treatment (that is not illustrated) by thethickness at a degree that the surface profile on the surface of theultra-thin copper foil 4 is not changed are performed.

It is preferable that the peeling layer 2 set on the carrier foil 1 is alayer consisting of Cr, Ni, Co, Fe, Mo, Ti, W, P and/or these alloylayer or these hydrous oxide layer, or is an organic film.

It is preferable that these metals (including alloy metal) and thosehydrous oxides forming these peeling layers are formed by cathodicelectrolytic treatment. Note that in a stage that wiring board that theultra-thin copper foil with a carrier foil is used is formed, forstabilizing the peeling after laminating the ultra-thin copper foil witha carrier foil on the insulating substrate, nickel, iron or these alloylayer may be set together under these peeling layers.

Preferable binary alloy of chromium alloy for the peeling layer 2 meansnickel-chromium, cobalt-chromium, chromium-tungsten, chromium-copper,chromium-iron, chromium-titanium. The ternary alloy meansnickel-iron-chromium, nickel -chromium-molybdenum,nickel-chromium-tungsten, nickel-chromium-copper,nickel-chromium-phosphorus, cobalt-iron-chromium,cobalt-chromium-molybdenum, cobalt-chromium-tungsten,cobalt-chromium-copper, cobalt-chromium-phosphorus, etc.

Moreover, in the case of using an organic film for the peeling layer 2,it is preferable that a thing consisting of one kind or two kind or moreselected from among an organic compound including nitrogen, an organiccompound including sulfur or a carboxylic acid is used.

The peel strength at the time of peeling the carrier foil 1 from thepeeling layer 2 is influenced with the amount of deposition of thesemetals. That is, if an peeling layer is thick (that is, if there is thelarge amount of deposition of plated metal), the surface of the carrierfoil is covered with the metal constituting the peeling layer(hereinafter called as peeling layer metal) completely, it is consideredthat the peel strength corresponds to the peeling power which tears offthe joint surfaces between the surface of the peeling layer metal andthe ultra-thin copper foil stacked afterward.

On the other hand, when a peeling layer 2 is thin (that is, if there isthe small amount of deposition of plated metal), the surface of thecarrier foil is not completely covered with the peeling layer metal, itis thought that the peel strength is the peeling power which tears offthe joint surfaces between the carrier foil which is exposed slightlyand the peeling layer metal and the ultra-thin copper foil deposited onthem. Therefore, although the peel strength of the carrier foil and theultra-thin copper foil changes with the amount of deposition of platedmetal that forms a peeling layer, if a peeling layer is formed(deposited) to some extent thickly, the peel strength will not changeany more. According to the experiment, as the amount of deposition ofthe metal, which forms a peeling layer, even if the amount of depositionof is made 100 mg/dm² or more, the peel strength does not change.

EXAMPLE 7

(1) Making of an Ultra-Thin Copper Foil

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.8 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, after performing strike plating by copperpyrophosphate plating solution, a copper sulfate solution described inthe following composition 4 was used as an electrolytic solution and theelectrolysis was performed in a condition that the current density was10 A/dm² to 30 A/dm² and the temperature of the solution was 40 degreesC. to 60 degrees C., an ultra-thin copper layer (copper foil) having thethickness of 5 μm was electroplated.

Condition of copper pyrophosphate strike plating Cu₂P₂O₇.3H₂O  5 g/l to50 g/l K₄P₂O₇  50 g/l to 300 g/l pH  8 to 10 current density  1 A/dm² to3 A/dm² treatment time  30 seconds (Composition 4) copper sulfate(CuSO₄.5H₂O) 250 g/l to 350 g/l sulfuric acid (H₂SO₄)  80 g/l to 120 g/l

(2) Surface Treatment

On the obtained ultra-thin copper foil, nickel-phosphorus plating(Ni=0.1 mg/dm²) and zinc plating (Zn=0.1 mg/dm²) were performed, furtheradditionally after chromate treatment (Cr=0.06 mg/dm²) was performed,epoxy silane coupling agent treatment (Si=0.0004 mg/dm²) was performed.

EXAMPLE 8

(1) Making of an Ultra-Thin Copper Foil

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.8 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, after performing strike plating by copperpyrophosphate plating solution equal to Example 7, a copper sulfatesolution described in the following composition 5 was used as anelectrolytic solution and the electrolysis was performed in a conditionthat the current density was 10 A/dm² to 30 A/dm² and the temperature ofthe solution was 50 degrees C., an ultra-thin copper layer (copper foil)having the thickness of 5 μm was electroplated. (Composition 5) coppersulfate (CuSO₄.5H₂O) 250 g/l to 350 g/l sulfuric acid (H₂SO₄)  80 g/l to120 g/l glue  1 ppm to 10 ppm Cl⁻  10 ppm to 50 ppm

On the obtained ultra-thin copper foil, the surface treatment similar toExample 7 was performed.

EXAMPLE 9

(1) Making of an Ultra-Thin Copper Foil

An untreated electrolytic copper foil having the surface (S surface)roughness of 1.8 μm and the thickness of 35 μm was defined as a carrierfoil and on the S surface chromium electroplating was successivelyperformed, a chromium plating layer (peeling layer) of the thickness of0.005 μm was formed. Next, after performing strike plating by copperpyrophosphate plating solution equal to Example 7, a copper sulfatesolution described in the following composition 6 was used as anelectrolytic solution and the electrolysis was performed in a conditionthat the current density was 10 A/dm² to 30 A/dm² and the temperature ofthe solution was 50 degrees C, an ultra-thin copper layer (copper foil)having the thickness of 5 μm was electroplated. (Composition 6) coppersulfate (CuSO₄.5H₂O)  250 g/l to 350 g/l sulfuric acid (H₂SO₄)   80 g/lto 120 g/l 3-mercapto-1-sodium propanesulfonate  0.5 ppm to 5 ppmhydroxyethyl cellulose   1 ppm to 10 ppm low-molecular-weight glue(molecular weight 3000)   1 ppm to 10 ppm Cl⁻   10 ppm to 50 ppm

(2) Surface Treatment

On the obtained ultra-thin copper foil, the surface treatment similar toExample 7 was performed.

EXAMPLE 10

(1) Making of an Ultra-Thin Copper Foil

As similar to Example 7, An untreated electrolytic copper foil havingthe surface (S surface) roughness of 1.9 μm and the thickness of 35 μmwas defined as a carrier foil, after performing electroplating ofchromium on the S surface and strike-plating by copper pyrophosphateplating solution, ultra-thin copper layer (copper foil) having thethickness of 6 μm was electroplated.

(2) Forming of Surface Unevenness

The surface was etched by 1 μm by etchBOND of MEC CO., LTD. The etchingcondition is indicated below. treatment chemical cz-8100 spray pressure2.0 kg/cm² treatment temperature  35 degrees C.

On the obtained ultra-thin copper foil, the surface treatment similar toExample 7 was performed.

EXAMPLE 11

(1) Making of an Ultra-Thin Copper Foil

As similar to Example 7, An untreated electrolytic copper foil havingthe surface (S surface) roughness of 1.8 μm and the thickness of 35 μmwas defined as a carrier foil, after performing electroplating ofchromium on the S surface and strike-plating by copper pyrophosphateplating solution, ultra-thin copper layer (copper foil) having thethickness of 7 μm was electroplated.

(2) Forming of Surface Unevenness

Treatment of making unevenness was performed on the surface of theultra-thin copper layer by the following condition. Theoreticaldissolution quantity is 2 μm.

Here, the theoretical amount of dissolution means the dissolutionquantity calculated from the applied electric quantity in the case ofdissolving in a state that electric efficiency is 100 percent. (a)composition of electrolytic solution: hydrochloric acid (HCL)   80 g/lto 100 g/l (b) temperature of electrolytic solution:   40 degrees C. (c)current density:   25 A/dm² to 40 A/dm² (d) treatment time: 12.5 secondsto 25 seconds

COMPARATIVE EXAMPLE 6

(1) Making of an Ultra-Thin Copper Foil

As similar to Example 7, An untreated electrolytic copper foil havingthe surface (8 surface) roughness of 1.8 μm and the thickness of 35 μmwas defined as a carrier foil, after performing electroplating ofchromium on the S surface and strike-plating by copper pyrophosphateplating solution, ultra-thin copper layer (copper foil) having thethickness of 5 μm was electroplated.

(2) Electrodepositing of Microscopic Roughening Grains

Cathodic electrolytic treatment was performed by direct current andmicroscopic roughening copper grains are electrodeposited on theultra-thin copper foil in the following condition. (i) Forming core ofmicroscopic grains (a) composition of electrolytic solution: coppersulfate (CuSO₄.5H₂O) 90 g/l to 130 g/l sulfuric acid (H₂SO₄) 110 g/l to140 g/l arsenious acid (As₂O₃) 100 ppm to 200 ppm (as As) (b)temperature of electrolytic solution:  30 degrees C. (c) currentdensity:  10 A/dm² to 50 A/dm² (d) treatment time:  2 seconds to 15seconds (ii) Capsule plating (a) composition of electrolytic solution:copper sulfate (CuSO₄.5H₂O) 200 g/l to 300 g/l sulfuric acid (H₂SO₄)  90g/l to 130 g/l (b) temperature of electrolytic solution:  50 degrees C.(c) current density:  10 A/dm² to 30 A/dm² (d) treatment time:  2seconds to 15 seconds

On the obtained ultra-thin copper foil, zinc plating (Zn=0.1 mg/dm²) wasperformed, further additionally after chromate treatment (Cr=0.06mg/dm²) was performed, epoxy silane coupling agent treatment (Si=0.0004mg/dm²) was performed.

COMPARATIVE EXAMPLE 7

(1) Making of an Ultra-Thin Copper Foil

As similar to Example 8, An untreated electrolytic copper foil havingthe surface (S surface) roughness of 1.0 μm and the thickness of 35 μmwas defined as a carrier foil, after performing electroplating ofchromium on the S surface and strike-plating by copper pyrophosphateplating solution, ultra-thin copper layer (copper foil) having thethickness of 5 μm was electroplated.

(2) Electrodepositing of Microscopic Roughening Grains

Cathodic electrolytic treatment was performed by direct current andmicroscopic roughening copper grains are electrodeposited on theultra-thin copper foil in the condition equal to Comparative example 6.

(3) Surface Treatment

On the obtained ultra-thin copper foil, the surface treatment similar toComparative example 6 was performed.

COMPARATIVE EXAMPLE 8

(1) Making of an Ultra-Thin Copper Foil

As similar to Example 9, An untreated electrolytic copper foil havingthe surface (S surface) roughness of 1.8 μm and the thickness of 35 μmwas defined as a carrier foil, after performing electroplating ofchromium on the S surface and strike-plating by copper pyrophosphateplating solution, ultra-thin copper layer (copper foil) having thethickness of 5 μm was electroplated.

(2) Electrodepositing of Microscopic Roughening Grains

Cathodic electrolytic treatment was performed by direct current andmicroscopic roughening copper grains are electrodeposited on theultra-thin copper foil in the condition equal to Comparative example 6.

(3) Surface Treatment

On the obtained ultra-thin copper foil, the surface treatment similar toComparative example 6 was performed.

Evaluation

For each ultra-thin copper foil produced in Example 7 to 12, Comparativeexamples 6 to 8, the surface roughness (ten point height of roughnessprofile) Rz of the ultra-thin copper foil was measured, and the resultwas indicated in Table. 2. TABLE 2 Surface Surface roughness ofroughness Roughness ultra-thin after of S Copper copper foil rougheningPeel Etching Carrier surface plating right after treatment strengthproperty foil (Rz: μm) solution plating (Rz: μm) (kN/cm) (L/S: μm)Example 7 35 μm 1.8 composition 1 1.9 1.9 1.00 10/10 MP foil Example 835 μm 1.8 composition 2 2.1 2.1 1.05 10/10 MP foil Example 9 35 μm 1.8composition 3 1.7 1.7 0.80 10/10 MP foil Example 10 35 μm 1.8composition 1 1.9 2.5 1.10 10/10 MP foil Example 11 35 μm 1.8composition 1 1.9 1.9 1.15 10/10 MP foil Example 12 35 μm 1.8composition 1 1.9 1.9 1.20 10/10 MP foil Comparative 35 μm 1.8composition 1 1.9 3.2 1.20 30/30 example 6 MP foil Comparative 35 μm 1.8composition 2 1.7 3.7 1.25 35/35 example 7 MP foil Comparative 35 μm 1.8composition 3 2.1 2.8 1.10 30/30 example 8 MP foil

1. Measurement of Properties

Since roughening treatment grains are not deposited, as is clear fromTable. 2, in an ultra-thin copper foil with a carrier foil of thepresent invention, the surface roughness is controlled small.

2. Measurement of Peel Strength

The peel strength of the ultra-thin copper foil with a carrier foilproduced in examples 7 to 12 and Comparative examples 6 to 8 wasmeasured. After the ultra-thin copper foil with a carrier foil was cutto 250 mm by 250 mm, a polyimide sheet (UPILEX-VT made by Ube Industry)was placed on the surface of the ultra-thin copper foil, the assemblywas sandwiched with two flat stainless steel plates, then the assemblywas laminated at the temperature of 330 degrees C. and the pressure of 2kg/cm² for 10 minutes by 20 torr vacuum press, then was laminated at thetemperature of 330 degrees C. and the pressure of 50 kg/cm² for 5minutes to produce a one-sided copper-clad polyimide laminated board forthe test of peel strength with a carrier foil. After peeling the carrierfoil, performing plating on the ultra-thin copper foil and making thethickness to be 35 μm, the peel strength was measured by 10 mm width.The result is indicated together in Table. 2.

As shown in Table. 2, Examples have sufficient peel strength.

3. Evaluation of Etching Property

After laminating the ultra-thin copper foil with a carrier foil ofExamples 7 to 12 and Comparative examples 6 to 8 on the polyimide sheet,the carrier foil was peeled.

After that, the test patterns having line/space=10 μm/10 μm, 15 μm/15μm, 20 μm/20 μm, 25 μm/25 μm, 30 μm/30 μm, 35 μm/35 μm, 40 μm/40 μm, 45μm/45 μm, 50 μm/50 μm (line length=30 mm, number of lines=10) wereprinted on the surface of the copper foil, and etching was performed incopper chloride etching solution.

The line width in the case that ten lines could be etched withoutbridging was indicated numerically in Table. 2. Etching was possibleuntil 10 μm or less in the ultra-thin copper foil produced in Examples,on the contrary, the minimum of the ultra-thin copper foil s produced inComparative examples was 30 μm.

As mentioned above, chemical treatment and/or electrochemical treatmentfor improving peel strength with a resin substrate was performed withoutdepositing roughening grains that etching speed is low on the ultra-thincopper foil with a carrier foil by the second and third embodiments ofthe present invention, or after performing treatment of makingunevenness by chemical etching and/or electrochemical etching withoutdepositing roughening grains that etching speed is low on the ultra-thincopper foil, further chemical treatment and/or electrochemical treatmentfor improving peel strength with a resin substrate was performed. As theresult, since in these copper foils, it is possible to etch untilultra-fine width that line/space is 15 μm or less, and peel strengthwith a resin substrate is large despite that roughness is low, it ispossible to produce printed wiring board with an ultra-fine pattern andmultilayer printed wiring board with ultra-fine pattern by theultra-thin copper foil of the present invention.

1. An ultra-thin copper foil with a carrier foil wherein a carrier foil,a peeling layer, an ultra-thin copper foil are electroplated in thisorder, and; said ultra-thin copper foil is an electrolytic copper foilthat has surface roughness of 2.5 μm as ten point height of roughnessprofile, and the minimum distance between peaks of salients of a basedmaterial is 5 μm or more.
 2. An ultra-thin copper foil with a carrierfoil wherein a carrier foil, a peeling layer, an ultra-thin copper foilare electroplated in this order, and; said ultra-thin copper foil is anelectrolytic copper foil that has surface roughness of 2.5 μm as tenpoint height of roughness profile, the minimum distance between peaks ofsalients of a based material is 5 μm or more, and a crystal grain havingaverage grains diameter is 2 μm or less is deposited on the surface. 3.An ultra-thin copper foil with a carrier foil wherein an exposed surfaceof said ultra-thin copper foil as set forth in claim 1 is performedchemical treatment and/or electrochemical treatment within a range thatprofile of said treatment side does not change.
 4. An ultra-thin copperfoil with a carrier foil wherein roughening treatment is performed on asurface of said ultra-thin copper foil as set forth in claim 1, and;said treatment side is performed chemical treatment and/orelectrochemical treatment within a range that profile of said treatmentside does not change.
 5. An ultra-thin copper foil with a carrier foilwherein a roughening treatment result of the surface of said ultra-thincopper foil as set forth in claim 4 is roughening plating by rougheningtreatment that a copper microscopic grain is electrodeposited.
 6. Anultra-thin copper foil with a carrier foil wherein roughening treatmentof said ultra-thin copper foil as set forth in claim 4 is chemicaltreatment and/or electrochemical treatment.
 7. An ultra-thin copper foilwith a carrier foil wherein said peeling layer as set forth in claim 1consists of Cr, Ni, Co, Fe, Mo, Ti, W, P and/or these alloy metal layer,or these hydrous oxide layer, or an organic film.
 8. An ultra-thincopper foil with a carrier foil wherein an exposed surface of saidultra-thin copper foil as set forth in claim 2 is performed chemicaltreatment and/or electrochemical treatment within a range that profileof said treatment side does not change.
 9. An ultra-thin copper foilwith a carrier foil wherein roughening treatment is performed on asurface of said ultra-thin copper foil as set forth in claim 2, and;said treatment side is performed chemical treatment and/orelectrochemical treatment within a range that profile of said treatmentside does not change.
 10. An ultra-thin copper foil with a carrier foilwherein a roughening treatment result of the surface of said ultra-thincopper foil as set forth in claim 9 is roughening plating by rougheningtreatment that a copper microscopic grain is electrodeposited.
 11. Anultra-thin copper foil with carrier foil wherein roughening treatment ofsaid ultra-thin copper foil as set forth in claim 9 is chemicaltreatment and/or electrochemical treatment.
 12. An ultra-thin copperfoil with a carrier foil wherein said peeling layer as set forth inclaim 1 or 2 consists of Cr, Ni, Co, Fe, Mo, Ti, W, P and/or these alloymetal layer, or these hydrous oxide layer, or an organic film.
 13. Aprinted wiring board characterized in that high density ultra-finewiring is performed by an ultra-thin copper foil with a carrier foil asset forth in claim
 1. 14. A printed wiring board characterized in thathigh density ultra-fine wiring is performed by an ultra-thin copper foilwith a carrier foil as set forth in claim
 2. 15. A manufacturing methodof an ultra-thin copper foil with a carrier foil comprising: a step ofperforming a carrier foil, a peeling layer and an ultra-thin copper foilformed by an electrolytic copper foil having surface roughness of 2.5 μmas ten point height of roughness profile, having the minimum distancebetween peaks of salients of a based material is 5 μm or more, andhaving a crystal grain having average grains diameter is 2 μm or lessdeposited on the surface in this order, and; a step of performingchemical treatment and/or electrochemical treatment onto an exposedsurface of said ultra-thin copper foil within a range that profile ofsaid exposed surface does not change.
 16. A manufacturing method of anultra-thin copper foil with a carrier foil comprising: a step ofperforming a carrier foil, a peeling layer and an ultra-thin copper foilformed by an electrolytic copper foil having surface roughness of 2.5 μmas ten point height of roughness profile, having the minimum distancebetween peaks of salients of a based material is 5 μm or more, andhaving a crystal grain having average grains diameter is 2 μm or lessdeposited on the surface in this order, and; a step that the surface ofsaid ultra-thin copper foil is performed roughening treatment, and astep of performing chemical treatment and/or electrochemical treatmentonto the treatment side of said ultra-thin copper foil within a rangethat profile of said treatment side does not change.
 17. A manufacturingmethod of an ultra-thin copper foil with a carrier foil as set forth inclaim 16 wherein roughening treatment of the surface of said ultra-thincopper foil is roughening plating that a copper microscopic grain iselectrodeposited.
 18. A manufacturing method of an ultra-thin copperfoil with a carrier foil as set forth in claim 16 wherein rougheningtreatment of the surface of said ultra-thin copper foil is performed bychemical etching and/or electrochemical etching.